Background: Appendicitis and its complications are the most commonly acute abdominal pain that require surgical intervention. Patients may present with a wide variety of clinical manifestation. The clinical diagnosis is based primarily on the patient history, physical examinations and white blood cell count. Clinical diagnosis mostly straight forward in patients presenting with classic signs and symptoms, while diagnostic confusion and delay in treatment may occur in patients with atypical presentations. MSCT is a highly accurate means for establishing the diagnosis. Objective: The aim of the work is to describe the value and role of Multi-slice computed tomography in diagnosing appendicitis and its complications. Methods: This study retrospective study was conducted on patients with right lower quadrant or right flank pain. The study was conducted in Health Insurance hospitals Radiology department on Fifteen patients with right lower quadrant pain or right flank pain. Results: In the present study, we concentrate on continuity and thickness of the appendiceal wall. The normal appendix thickness is less than 1 mm. When appendix got inflamed, it usually appears thickened, asymmetric and enhancing with i.v. contrast from 1 to 3 mm thickness. Conclusion: MSCT is helpful for accurate and prompt diagnosis in suspected cases of appendicitis & its complications and conditions that mimic appendicitis.